I’m sure there are very many people who feel the Extinction Rebellion (XR) protests in London over Easter mark a watershed.

First, there is the scale. There have been important direct action movements. Probably the biggest was the Committee of 100’s campaign against nuclear weapons in 1961-62.

But I can’t think of anything that has been as sustained as this—thousands of people in a week so far of highly disruptive protests in central London.

No doubt the British state, presided over by a weak, divided and distracted government, is on the defensive. But XR’s achievement is remarkable.

Secondly, there is the issue. Almost everyone recognises that climate change is happening and is caused by human action. Almost as many people recognise that the establishment has not begun to do what is needed to stop catastrophic increases in global temperatures.

But increasing numbers believe we have little or no time left. A widely read paper by Jem Bendell of Cumbria University argues that the scientific evidence suggests it is “too late to avert a global environmental catastrophe in the lifetimes of people alive today”.

Climate change involves a variety of processes that may be on the verge of mutually reinforcing each other. For example, the Arctic is rapidly melting. This could lead to the release into the atmosphere of methane—an even more potent greenhouse gas than CO2— currently trapped in permafrost.

Bendell cites a study that warned of “atmospheric heating of over 5 degrees within just a few years of such a release”.

His conclusion is grim. “We are set for disruptive and uncontrollable levels of climate change,” he writes. “I mean in your own life.

“With the power down, soon you wouldn’t have water coming out of your tap. You will depend on your neighbours for food and some warmth. You will become malnourished. You won’t know whether to stay or go. You will fear being violently killed before starving to death.”

But more and more people fear that he is. It is this that has swept so many people behind XR’s banner and that motivates the school student strikes.

This poses a challenge for the left. There are various great Marxist studies that show climate change and the broader process of environmental destruction are a consequence of the drive for capital accumulation.

But this kind of theoretical insight still needs to be translated into political practice. Like the big parties, socialists have been obsessed and divided by the Brexit crisis. Meanwhile, the organised left has been largely missing from the XR protests.

It’s easy to pick holes in XR’s strategy. On the one hand, The Ecologist magazine says, “Extinction Rebellion is forging an international solidarity network to challenge capitalism, neo-colonialism and extractive industries.”

On the other, the Financial Times newspaper describes co-founder Gail Bradbrook, “dashing between fundraising discussions with a London hedge-fund owner and meetings to rally Extinction Rebellion volunteers”.

A hedge-fund owner? A War on Want report in 2016 found that firms listed on the London Stock Exchange control £166 billion worth of coal just in Africa and are drilling for oil in 27 African countries.

It would be absolutely criminal to make contradictions like this an excuse for not taking part in these new climate movements. Every new struggle draws in many people with a mixture of sometimes incompatible ideas.

The problem up to now has been that the sheer enormity of the threat of climate catastrophe has tended to induce passivity and despair. Now this is changing. Good—we should be part of this.